Every negotiation guide on the internet is written for someone who has a competing offer. Most people reading them have exactly one. Open the top result for "how to negotiate a job offer" and count how many of its moves survive the sentence "I do not have another offer." Haseeb Qureshi's rules say it outright: the strongest determinant of your final offer is the number and strength of the offers you hold. Candor says the most reliable way to get more money is a competing offer.…